Generic drugmakers colluded to jack up the price of a common skin medication by more than 1,100 percent in just three months, according to a lawsuit filed by a city police union.

The price of Clobetasol, used to treat eczema, psoriasis and poison ivy, skyrocketed after six pharmaceutical companies got together in Maryland in 2014 for their annual conference.

There was no manufacturing, medical or competitive reason for the eyebrow- raising price hikes, which were the result of a “coordinated decision not to compete,” claims the lawsuit, filed Friday in Manhattan Federal Court by the NYPD’s Sergeants Benevolent Association.

In 2013, a 60 gram tube of Clobetasol cost just $15.60, but last year, the same tube hit $250, according to court papers.